If they're banned from the site, then how are they supposed to read this message? How about a global email instead to all members?

The ban merely prevents the user from registering/logging in. They can still read the forum. Just happened to TheOddFind, and to Glassbreaker last week. Not sure what's causing it, but we're looking into it.

I don't think ass is on the banned list. Otherwise, you wouldn't have just read it. It has something to do with our Cloudflare service blocking a perceived threat (most likely a false positive) or the forum's firewall, but it's only effecting a few users. Someone launched a mild DDOS attack on us (I can only assume a competitor is responsible), but luckily the Cloudflare service plan we're on has level 7 protection, so it's more of a minor annoyance than an actual threat.